Auxiliary telephone apparatus



A ril 4, 1944. c. s. RHOADS AUXILIARY TELEPHONE APPARATUS Filed April22, 1943 B'Y C. YW

INVENTOR ATTORNE Patented Apr. 4, 1944 AUXILIARY"TELEPHONE APPARATUS'Oharles stanley Rhoads, Albany, N. Y., assignor :to American'TelephoneandTelegraph m- 1: pany;-a corporation of New York 'I.ApplicationApril22, 1943, Serial No. 483,983

3 Claims.

This invention relates generally to telephone systems. Moreparticularly,'.thisinvention relates to apparatus for signaling betweentwo telephone ofiices over trunk or other lines. Still moreparticularly, this invention relates to auxiliary or emergency equipmentfor use at telephone offices to provide iacilities for signaling betweenthe offices under abnormal conditions.

It sometimes happens that a community or hamlet too small to justify anordinary manual exchange is located near a city provided with a regulartelephone exchange or exchanges. Such an outlying hamlet may be providedwith te1ephone service by means of a community dial ofiice which may beequipped with relatively simple automatic switching machinery to enablethe local subscribers to dial each other. -An operator in the city mayestablish -a direct connection over one of a group of trunks extendingto the community dial ofiice to any desired subscriber coming into thecommunity dial oiiice, and any local subscriber who desires a connectionto the city may by dialing be connected over one of these trunks to anyof the city subscribers. Such community dial offices are usuallyunattended, except at such time as maintenance or inspection employeesmake temporary Visits to inspect or test the apparatus at the office.

It may happen that when an employee has been dispatched to the communitydial ofilce to test or inspect the equipment he may find that theequipment has been partially or totally destroyed, or that the powersupply has been rendered inefiective. In that case he will be unable tocommunicate with the operator at the manual or operator ofiice. As thecommunity office may be several miles distant from the main office, it

will be necessary for the telephone employee to return to the operatorofiice to deliver hismBssage. This is, of course, time consuming andexpensive.

Accordingly it is proposed to equip telephone oifices such as community.dial offices and manual or operator. ofices and the-like, with auxiliaryor emergency equipment to enable signals to be transmitted between theseofiices'whenever the regular equipment has been disabled. The

apparatus of this invention involves'the employment of equipment at the'various 'oi'hces which will not consume'current under normalconditions; although at the same time the equipment'willalways'bebonn'e'cted to the telephone not affect normal telephonetransmission over the line or trunk.

In general, the apparatus of this inventionwill comprise a gas tube ateach oflice which is connected to but one of the conductors of thetelephone line or trunk so that it may be fired only at times when aringing generator is connected to that particular conductor of the lineor trunk. When the gas tube at the'station is fired in response to theapplication of the ringing generator voltage to the particularconductor, it will be employed to provide a signal to attracttheoperators attention at the time. The ringinggenerator voltage forfiring the gas tube may be supplied by a magneto generator set of wellknown type. The magneto generator set can produce an alternating voltageof sufficient magnitude to cause the gas in the tube to become ionized.The apparatus at each oflice may also include, in addition to a visualor, audible indicating device, th usual form of telephone transmitterand receiver to permit the parties to speak to each other. Whateversources'of' D. C. potential may be required may be supplied 'by drycells. In accordance with this invention 1 all of the auxiliaryemergency equipment at the stations will be efiectively dissociated fromthe telephone line or trunk and will not interfere with normal signalingand communication over the telephone line or trunk. Moreover, theauxiliary or emergency equipment, although connected to p the telephoneline or trunk, may be'located at a connect a subscriber in the communitydial area to a subscriber in the area'of the operator ofiice. Theregular office equipment so far as it may relate'to this invention isshown above the-dotted line. Below the dotted line will be-found theauxiliary or emergencyequipmentwhichis additional equipment differentfrom that heretofore used in such offices and may be employed only 3 inemergencies.

" line or'"trunk" foruse lrr'emergencies; and will now be only brieflydescribed.

The regular equipment ofthe two officeswill The windings of relays W andP at the community dial ofiice and at the operator oflice, respectively,are connected in a series circuit which includes the upper winding ofrelay W, the upper secondary winding of the repeating coil RLI, theupper armature and normal contact of relay U, the upper conductor oftrunk TK, the upper primary winding of repeating coil RLz, the windingsof relay P, the lower primary winding of repeating coil RLz, the lowerconductor of trunk TK, the lower armature and normal contact of relay U,the lower secondary winding of the repeating coil RLi, the lower windingof relay W, battery to ground. The current that traverses the windingsof the relays W and P will be insufiicient to operate these relays, butthey may be operated as will be described hereinafter whenever a call ismade from, for example, the subscriber connected to the community dialomce to a subscriber connected to the operator oflice,

When a call is being made by a subscriber of the community dial ofiiceto a subscriber connected to the distant operator office, then inresponse to a predetermined dialed number, battery will be connected tothe conductors T and R,

causing relay S to operate. Positive battery will be connected to thetip conductor T to energize the upper winding of relay S while groundwill be connected to the ring conductor R to energize the lower windingof relay S. The operation of relay S will cause relay U to operate overan obvious circuit established by the armature and make contact of relayS. When relay U operates, it will reverse the direction of current fiowfrom the battery connected to the lower winding of relay W through thewindings of relay P. This reversal is established by the upper armatureof relay U which connects the grounded upper winding of relay W to thelower conductor of trunk TK and by the lower armature of relay U whichconnects at the lower winding of relay W to the upper conductor of trunkTK. Upon the reversal of current through the windings of relay P, relayP will be operated. The operation of relay P will cause the lamp LP1 tolight, thereby attracting the atention of the operator at the operatoroflice.

In response to the visual signal provided by lamp LPI the operator atthe operator office may answer the call by inserting her plug into thejack JK], in the usual way. This will connect battery to the tip andring terminals of the jack JKI to establish a flow of current throughthe secondary windings of the repeating coil RLz and the winding ofrelay V, and hence relay V will be operated. The closure of the contactof relay V will provide a shunt path across the left-hand portion of thewinding of relay P, thereby materially reducing the resistance in thecircuit of the remaining winding of relay P. This substantial reductionin resistance will allow a greater current to flow through the windingsof relay W over the circuit previously traced, and hence relay W will beoperated. The relay W may be used to control coin collector apparatusand for other purposes.

Suppose that in an emergency a repairman or other authorized person hasbeen dispatched to the community dial oifice, and upon arriving at theoffice, finds some of the regular equipment out of order or the batterysupply disabled so that he is unable to use the regular equipment tocommunicate with the operator oilice operator. He will find at thatofiice auxiliary equipment which will enable him to signal and conversewith the operator at the operator ofi'ice.

To signal the operator omce the party at the community dial office willoperate the magneto generator G of the magneto set located at thatoffice while the receiver RR. is held on its switchhook. This will causean alternating voltage to be generated and transmitted over a circuitwhich includes the condenser K1, the magneto generator G, the lowerconductor of trunk TK, the control gap of the gas tube TB1 at theoperator ofiice and ground. The anode AN1 of the tube T31 is shownconnected to the left-hand winding of relay A, and hence this winding ofrelay A will receive current supplied by the magneto generator G afterthe tube TB1 becomes ionized. It will be noted also that the gas tubeTB2 at the community dial oflice is connected to the generator G, andhence this tube will likewise be fired. Inasmuch as the anode AN2 oftube TBz is connected to ground through a ringer or bell BL, the ringeror bell will be operated in response to the generated alternatingvoltage.

As relay A becomes operated in response to the alternating voltageemanating from generator G, it will be locked in its operated positionover a locking circuit which includes the armature and make contact ofrelay A, its right-hand winding, the contact 0 of the jack JK3, the lampLP2, battery and ground. As the lamp LP; is included in the lockingcircuit, the lamp LPz will be illuminated and maintained in thatcondition to continuously indicate to the operator at the operatoroifice that an emergency call is being made to that ofiice. The relay Awill remain locked and the lamp LP2 will remain illuminated until theoperator at that oifice answers the call.

The emergency call may be answered by the operator by inserting the plugof her talking set into the jack JK3. The lamp LP2 will then beextinguished by the opening of contact C. This will connect her talkingset through condenser K2 across the trunk TK. Upon the removal of thereceiver RR from the hook at the community dial office, the receiver RR.will be connected across the trunk TK by two conductors, one of whichincludes the secondary winding SW of the magneto coil, the otherconductor including the condenser K3. A the transmitter TR. of thetelephone set is connected to the circuit of the primary winding PW ofthe induction coil of the magneto set, it will also be renderedefiective so that the party at the community office may talk with theoperator ofi'lce operator.

Should the party at the community dial office hang up before theoperator has completed her conversation with him, or if the operatorshould desire to recall that party, the operator will connect the plugof her ringing generator set with the jack JKz. This will cause the gastube TBz of the community dial oifice to receive ringing current over acircuit which includes the tip and ring contacts of jack JKz, the lowerconductor of trunk TK and the control gap of tube T32 and ground. Inresponse to this ringing current the gas tube TB: will become ionizedand the bell BL will be sounded. In answer to this signal the party atthe community dial oifice may then remove his receiver RR from theswitch-hook and receive the message from the operator at the distantofiice.

It will be observed that the additional auxiliary equipment at the twooifices is simple and inexpensive and that, although permanentlyconnected to the trunk TK,.itwill have practically no effect upon thetransmission characteristic of the trunk TK. Hence the auxiliaryequipment will not interfere in any Way with the normal transmission ofsignals over the trunk TK. Moreover, normal transmission over trunk TKwill not operate any of the auxiliary equipment. Whatever batteries areused in the auxiliary equipment may be dry cells, and they will have along life due to the small drain of current required to provide thisoccasional service. The tubes T281 and T32 may be any type of gas tubeswell known in the art, although tubes of the 333A type have been usedsuccessfully for this purpose.

While the emergency equipment has been shown connected to a communitydial office and to an operator or manual ofiice which is attended by anoperator, it will be understood that this emergency equipment may beprovided for any telephone ofiices whatever. Moreover, the emergency orauxiliary equipment may be located at places difierent from and outsideof the central ofiices, if so desired. It will also be understood thatthe arrangement shown'and described in the drawing may also be used asregular telephone equipment, if so desired.

While this invention has been shown and described in certain particularembodiments merely for the purpose of illustration, it will beunderstood that the general principles of this invention may be appliedto other and widely varied organizations without departing from thespirit of the invention and the scope of the appended claims.

What is claimed is:

1. In a telephone system, the combination of two telephone ofliceshaving telephone and signaling apparatus and interconnected by atelephone line so that signals may be transmitted normally over saidline, apparatus for providing emergency service over said telephoneline, said apparatus including a gas tube at each telephone ofiiceconnected to but one of the conductors of the telephone line, means forapplying ringing current to the same conductor of the telephone line forfiring said gas tube, a ringing device at each ofl'lce which responds tothe firing of the associated gas tube, and means including a telephoneset for connection across the telephone line to permit talking currentsto be transmitted over the line.

2. The combination of two telephone offices, a two-wire lineinterconnecting said telephone offices, said telephone ofiices includingapparatus for normally signaling over said line, auxiliary apparatus forsignaling over said line without disturbing normal signaling betweensaid telephone offices, said auxiliary apparatus including two gastubes, one located at each ofiice and connected to but one of the wiresof said line, an indicating device at each ofiice controlled by the gastube at that office, a magneto generator at each office which may beconnected to one wire of the line for ionizing the gas of the tubes atsaid ofiices, and means for transmitting and receiving telephonecurrents over said line.

3. In a telephone system, the combination of a main ofiice which isattended by an operator, a community dial oflice which is usuallyunattended, a trunk interconnecting said ofiices, said ofiices includingapparatus suitable for normally signaling each other over said trunk,emergency signaling equipment at each ofiice, the emergency signalingequipment at the community dial ofiice including a first gas tubeconnected to but one of the conductors of said trunk and a magneto setwhich may be operated after the first gas tube has been fired, theemergency signaling equipment at the main oflice including a second gastube connected to the same conductor of said trunk, a relay controlledby said gas tube, and an indicating device controlled by said relay,said emergency signaling equipment at both offices being continuouslyconnected to said same conductor of the trunk and having substantiallyno effect upon normal transmission between said offices over said trunk.

CHARLES STANLEY RH-OADS.

